Grinder



Feb. 6, 1940. H. A. MAURER 2,139,015

GRINDER Filed Jan. 11, 1937 ZSheets-Sheet 1 QWA/Z A 1 N VENT OR.

BY f/arm/ CZ. 777mg? y 1mm.

Feb. 6, 1940.

' H. A. MAURER GR INDER Filed Jan. 11, 1937 2 Sheets-Shet 2 uh I jINVENTOR. f/arrq dwaw'e' g ATTORNES- Patented Feb. 6,

. g I GRINDER Harry A. Mam, Noveltyrohimassignor mate 1 OsterManufacturing Company, v Ohio, a corporation of Ohio Qleveland;

'Applicatiovn january 1 1, 1937, serialN o. 11$,9'76 v Thisinvention,pertainsr'to a, zg'rinding machine \of universal-applicationwithin its I'field and comprising an arrangement of 'motive power,..

stand, and Wheels all particularly ad'aptedfor use therewith, andwork-holding means also particu-x larly adapted to use therewith, suchWork-holding means comprising a number. of .modificaticns ofdetail-within the-same principle, for-holding, for sharpening ordressing all mannerof threading or cutting dies or chasers.-'- A method'of sharpen- --ing oz-"clressing a plurality of .chasers to uniformdimensions is also-included in the invention,- this method being adaptedfor, vbut notllimited to. performance by my improved machine.

" 'To the accomplishment i Qf the foregoing and related ends, saidinvention, then, consists; of

th'e'means hereinafter fully described; and par ticularly pointed out inthe "claims. 1

The annexed drawings andt-he following description set forth in detailcertain mechanism embodying the invention,- such disclosed meansinvention may be use'dlfi constituting, however, but j'one' c t variousmechanical vforms in which the principle of the In the accompanying,drawings: l Fig. l is a side elevation showing apreferred embodiment ofmy improved grinder; Fig. 2 isa plan view of the same grinder, butshowing a different grinding wheel attached thereto;

Fig.3 is a plan View of the work holding' chuck showing a grindingwheelin'relation thereto; ,Fig. 4 isanv enlarged diagrammatic verticalsection illustrating the action of a grinding wheel on a chasertoproduce the correct contour for working clearance; I I

Figs. 5 "to 11' inclusive are different types of chasers;

Fig. 12 is a face view of the movable jaw of the Work-holder, the pointof view being the plane |2- l2, Fig. 5,--looking.in' the direction ofthe arrows and omitting-the work piece;

Fig. 13 is aface view of the movable jaw of the *workaholdenjthe pointof-view' being the plane l3'-.-l' 3, 6,1ooking-in the direction of thearrows and'omitting the workpiece; and

Fig. 14 is a partial yertical section on plane |4- l4,.Fig."11.

comprises a base In and vertical standard H. The base carries a table 12"slidable toward and away from the standard on ways 13 .bymeans ofascrew M manually operated 'by'crank I5. An

upper table IG issIidable longitudinallyof the rscrew 32.

some similar arrangement.

plan 1 views showing "several various arrangements of the holder for Themachine, in its preferred "embodiment,

' table IZ ,-'that transversely of the ways 13.

On this" table it the work-holding chuck is the base. iii, forxrotat'ionabout its own vertical axis, and can be clamped against-rotationbyset Aunitary assembly of'mctor 33 and grinding wheel M is raised and loweredon the 'mounted, consisting in detail of a foundation j plate 26,a*turret he'ad'Zi and'positioningjaws22,

.213 respectively stationary and movable.

. The standard I l is rotatable in asocket 3! of.

etandard i by the crank 35 operating a threaded shaft 3% with, whichtheframettl of the assem-l \blyislconnected through a slot in thestandardaii by the usualarrange nent of a traveling nut, not I shown, orother suitablemechanism. The set screw 38 clamps the frame 3'31 againstmovement on the standard? t loads, and thusmsafeguard against, burstingthe wheel whenv idle a resistance coil is carried im- Jnediatelyf-uponthe motor case, covered by Ventilated shield ti). ,"Ihe arrangements forfastening various sizes of .grindingwheels, suchas 3t or 34A, to; themotor spindle are conventional and not shown in detail. The grindingwheel is Fo-r convenient portability a flexible card 42 with the usualplug 43 and switch guarded as at 39'.

it. are provided. It; is contemplated that the grinder" willordinarilybemade in a bench size, and may be moved from place to place,being carried for example ona wheeled Workbench or :Thechuck includesthe base piaceflzo and top To hold the motor to uniform speed atvaryi'ng1 plate f2! vertically pivoted thereto and capable of being fastened byalock nut 53in any l'angular position within its range "of motion, asindicated by 'the index 5 I. The positioning jaws,-bothof which: areordinarily flat plates of about or :less than,1.the'thickness'0f achaser, on the-order of one-half inch more or less, and. horizontallyplaced,.Garried on thepupper plate, comprises a segmental-jaw 22 movableas-in Fig-3 and with clamping means 55-for, jaw 22 including" a-En-utand a bolt the head of which travels in an underout slot 55, andanothermovablejaw 23:with adjustment transverse to the movement of -22,:=by

slots :56, and clampedf-by nuts 51. :Where the .j aw

vforms are modifiedythey are designated inthe Qdrawingsas 23A and 2333;,

Asshown in" Figs. 12. and 13; the inner surface dearth of thesejaws-contains a seriesof horizontal holes; '16 and H threadedandpilotedgfor I the insertion of pins whereby the work can be setaccording to critical surfaces and dimensions,

although,'to- .avoid complication of :the drawings,

long wide shank and a scroll-cam recess 75 at the side. In this type ofchaser, the forward edge.

only the holes which are in use are shown in Figs. 5 to 11 inclusive.

Further details and modifications of the chuck In Figs. 2 and 3 a chaserC. is shown having a 16 of the recess I5 is the base with referencetowhich feed of the cutters is regulated. Consequentlythis is the datumfor grinding work, and the cutter C is held thereto by a pin. in e I lipgrindi g, the feed between successive cutsis appropriate one of theholes ll]. The preferred form of pin is screw threadedand piloted, withI I a3ll, while in throat grinding .the feed'is by the, handle I5 andscrew I4, as'already mentioneds a projecting head it, all asshownin Fig.5,

; but other forms of pin may be used. I

Further setting, if necessary, is by sliding the plate.22 and lockingthe fastening 55 in theslot 55. Thereafter, feed across the face of, thegrinding wheel is accomplished bytraversing the slide I6 by hand. Feedagainst the-wheel for throat grinding, Fig. 2, is obtained by the feedscrew M, but feed against the wheel for lip grinding is by the handle 35and vertical feed screw 36, moving the wheel downfto the -work, as inFig. 1.. I I i Fig. 5 shows the set-up for a small shortshanked chaserC. Here the datum surface-is the outer end of the chaser, which isestablished. against the head 18 of the pin H in the app'ropriate hole10 in the plate 22. In'Figg, 6 the arrangement is similar to that. ofFig.3 but reg versed, with the front edge of thescroll-icam recess 80 ofthe chaser C positioned against a screw in one of the holes i l in thejaw 23.

Fig shows a set-up for awide short chaser C Here a long pin 8! is usedin the proper hole,

70. The jaw plate 22 is here shown slightly offset from concentricitywith the plate 2|, to 'adjust the chaser C3 position an amount less thanthe distance between successive holes it. The

opposite chuck plate 23A is modified, having eral support to the insetside of this chaser.

In Fig. 10 the chaser C is a modification of that shown in Fig. 6, andis positioned for depth by the'pin T! and held laterally by the wideheadof pin 82. I I V In Fig. 11 the chaser C is longer than the chuckdiameter and also. is of a type in which i the feed scroll engagement isby a side stud .90.

cutting chasers areon the lip: and on the throat. The former is shown inFig. 1, where B indicates the lipangle and the latter by Fig. 2 whereDindicates the throat angle. It will be observed that the lip angle B isestablished by inclination of the face of the grinding wheel 34, shownin Figs. 1 and 3, whereas the throat angle" D is established by theinclination of the face plane the axis. of rotation.

of the chaser teeth with the he, of the grindingi wheel, inthis instance34A. i Various sizesand shapes oflgrindirig wheels maybe employed asqrequired.

Since the angle does not change eXcept 'by; I changingthe wheel 3d; andsince the angle D can be fixedby clamping the turret- 2| (index 5l it Imay begracluated intennsof thisang le) it will,

be seen that to! grind .aqset'of 'chasers uniformly I I to any required.angle and depthall that is necessary is to'setup the grinder and makesuccessive passesor cuts. by traversing the carriage lffi'.

accomplished by the handle-35 and vertical screw Consequently, to grindall fourchasersof a set the pinsy afford afumI'locatingfit. I

After the turret-chuck is set up for the-chasers, chaser No. 1 of thesetis placed in the chuck,

and passed oncea'crossthe wheel by sliding the table it by hand. Withthe other hand the operator maintainsa lightrpressure' on the chaser,

keeping it positioned. in the chuck. After one pass across the face ofthe grinding wheel he lays it to one side, returns: the table tostarting. position, inserts chaser l \.T o. 2 of thesame'isletin thechuck, passes it across the wheel, removes vit, and so on, asbeforefalways picking up his chasersin the same order and making onlyone pass at a. time with each chaser of the series, until the requisiteamount of grinding has been Theimethod of grinding the lip is-indi icated by Figs. '3 and. 1, and'throat grinding by 7 i done.

Fig. 2.'

. It .will be. understoodfby those. skilled in the art thatfor. throatgrinding the wheel 34A must I I be of the same.radius'as'thei'curvatur'ei of thek chaser threads. Fig; 4. illustrates.the pra-ctice in grinding the chaser' throat," where the grind ingwheersiA, ,indicated'by a solid circumfer- J.

ential-line, is centeredfa't E, and-thenoncave throat curvatureexactlyflts the'whee'l circ1'1rn.-'v

i'erence, since it is ground in by the. wheel; The

broken circle P indicates the circumference 0fa"v pipe or a rod Wbichthechase r C- is. intended: to 1 thus apparent that only thefront'edge Gof. the.

throat (more strictly'speaking," the point of each thread, this circlebeing centered. at It 15 tooth) will contact the pipe. 1 Thedivergenceof the clearance betWeenIchaser and'work in thread cutting.

circle P from the solid circle below'G indicates I I I It will likewiseJ be. apparent .to those Ski1Ied:

in the-art that myz improved"tool can alsof b'eused for dressing the,grinding wheels by insert? ing a dressing stickinto the chuck instead"of Ta chaser, and bringing the stick into proper rela tion with thewheel; For dressing a. cylindrical,

wheel, the stick will be arranged square-to the" wheel, that isywith the'dr'essing'edge' parallel" to For dressing a conical wheel, the standardiii carrying the grinding unit will .be'turned through ahorizontatangle,

the Wheel edge at the ap'propriateangle. 1'- This angle can be madeentirely by; turning the stand". I ard i l, or .partly-byturningthefstandard .H and partly by turning the chuck turret 2!." While thewheel is in rotation the stick is traversed across the face by slidingthe carriage 5.

To maintain nearly uniform speed under both working and idle conditions,thus avoiding excessive idling speed with consequent danger of wheelexplosion, I provide a resistance coil in the armature circuit of themotor. The preferred motor is a constant speed universal type,

of suitable voltage for use on lighting circuits.

This resistor, a permanent part of the apparatus, is housed by theshield 40, perforated for ventilation. The action of the resistor inmaintaining uniform speed does not impair the efficiency ofthe motorunder load. This constant speed feature is not in itself a part of myinvention, since the resistor is provided by the motor manufacturer.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the mechanismherein disclosed, provided the means stated by any of the followingclaims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a chaser grinding machine comprising a; wheel and a horizontaltraversing table, the' combination with said table of a pair ofrelatively movable plates thereon, said plates in-- cluding verticalinner edges defining between .them the walls of a groove whereof thetable inner edges defining between them the walls ofa groove whereof thetable forms the bottom, a chaser-positioning element, and a plurality ofpositive engaging means between said groove and said chaser-positioningelement for holding the latter in said groove, said edges and saidchaserpositioning element being adapted to establish positioning contactwith controlling surfaces of a chaser laid on said table in said groove.

HARRY A. MAURER.

